Variable-resistance device



Sept. 30, 1924.

| SUTHERLIN VARIABLE RESISTANCE mayxcs Filed Sept. 27, 1922 INVENTOR Lee Samar/171 ATTORNEY Patented Sept. 30, 1924.

UNITED STATES PATENT OFFICE.

LEE SUMMER, OF EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO WESTING- HOUSE ELECTRIC AND IANUF ACTURING COMPANY, A CORPORATION 01 PENN- BYLVANIA.

VARIABLE-RESISTANCE DEVICE.

Application filed September 27, 1922. Serial Io. 590,811.

'To all whom it may concern:

Be it known that I, Lna SUTHERLIN, a citizen of the United States, and a resident of East Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Variable-Resistance Devices, of which the following is a specification.

My invention relates to variable-resistance devices and more especially to variablegrid-leak devices.

In its broad aspect, an object of my invention is to provide variable-resistance apparatus wherein the resistance is continuousl variable within wide limits.

ore specifically, an object of my invention is to provide variable-grid-leak apparatus which is characterized by its simplicity of design and ease of operation and which embodies parts suitable for quantity-production methods of manufacture.

In carrying my invention into practise, I provide a variable-grid-leak device comprising a container having a solution therein and means for varying the effective resistance of the solution a predetermined amount upon a predetermined relative movement of said. means and said solution.

With these and other objects in view, my invention further consists in the combinations, the mode of operation and the constructional details hereinafter set forth and claimed and illustrated in the accompanying drawing, wherein Fig. 1 is a front elevational View, shown partially in section, of a preferred form of embodiment of my invention;

Figs. 2, 3 and 4 are detail views illustratin modifications.

n the preferred form of embodiment of my invention, shown in Fig. 1,'I provide a horizontal elongated tube 1 composed. of glass or other insulating material and havmg a small quantity of a conducting liquid or electrolyte 8 therein. A pair of wires 2 and 3, servin as electrodes, are mounted at opposite en s of the tube 1 and have helical portions 4 and 5, res ectively; The wires 2 and 3 may be exten ed through the ends of the\ glass tube 1 to provide 'external connections 6 and 7 respectively, for the same.

The tube is mounted for rotation about its horizontal axis, as by means of a handle or Ie ngth knob 1', and the amount of liquid 8 in the tube is such that a path is prov'ded between the portions of the two, wires 2 and 3 which are, at any time, positioned along the lower part of the tube. As the tube is turned upon its axis, say, about three-quarters of a rotation, a path will be provided between different portions of the electrodes 2 and 3, say the points a, c, and

(1, respectively. Thus, the effective of the path provided by the liquid 8 between .the electrodes 2 and 3 may be continuously increased from a path of length w-b to a path of length c-d. The remaining space in the tube; 1, which is not occupied bythe electrodes 2 and 3 and the conducting liquid 8, may be filled either with air or with inert gas or it may be evacuated, as desired.

As may readily be seen, ,manydiifercnt liquids or mixtures may be employed, according to the specific application of the resistor element. I have found that, in applying my' invention to vacuum-tube circuits as a variable grid leak, a solution comprising a mixture of alcohol and xylol gives satisfactory resistance variations, as from 200,000 ohms to 2 megohms. The tube 1 may be mounted for rotative movement about its longitudinal axis by securing opposite ends thereof in ferrules 9 and 10 aving bearing portions 11 and 12 carried by bearing posts 13 and 14:, respectively, the latter, in turn, being supported upon a block 15. a

In summarizing the operation of the device shown in'Fig. 1, it 1s seen that the effective resistance of the solution 8 or, in other words, the length of the path between the portions of the electrodes 2 and 3 which are immersed in the solution 8, is continuously Variable for a rotative movement of the tube 1, the amount of such variation depending upon the relative curvatures of the portions 4 and 5 of the tube wires 2 and 3.

The modification shown in Fig. 2 is distinguished from the structure of Fig. 1 in the replacement of the co-operating portions a, a and b, d of the wire electrodes v the inside surface of the tube 1 and be conrotated, in this combination, the effective nected to the outside of the tube 1 by means of conductors 21 and 22, respectively. operation of this structure is exactly the same as that of Fig. 1, the length of the non-conductive portions of the tube 1 or, in other words, effective resistance of the electrolyte 8, varying with the rotation of the tube 1.

The modification shown in Fig. 3 is differentiated from that of the previous figures in the employment of a single spirally curvedconductor 23, solution 8 constituting the other co-operating conductor. In this modification, the conductor 21 of Fig. 2 is extended to form a fiat cylindrical portion 24, some part of the latter being continuously immersed in the solution 8 throughout the rotative movement of the tube 1. In operation, the effective resistance of the liquid 8 varies from a minimum value, with the tip of the electrode 23 just engaging the surface of the liquid 8, to a maximum value with a more remote portion 25 of the conductor 23 engaging the surface of the liquid 8.

The arrangement of the apparatus shown in Fig. 4: is exactly the same as that of Fig. 3 with the exception that the low-resistance conducting wire 23 of Fig. 3 is replaced by a high-resistance wire 26. In addition, the high-resistance solution 8 of Fig. 3 is replaced by a relatively low-resistance solution 27 in Fig. 4. When the tube 1 is length of the resistor element 26 is varied as a greater or less amount thereof is passed through the solution 27, thereby varying the ffective resistance of the element 26.

Although I have shown several possible modifications and applications of my invention and although I have mentioned specifically the nature of certain elements, for the purpose of describing my invention and more clearly illustrating the underlying principles thereof, it is apparent that my invention is not to be strictly limited thereby and that various changes and modifications may be made without departing from the spirit thereof, I desire, therefore, that only such limitations shall be imposed thereon as are indicated in the appended claims or demanded by the prior art.

I claim as my invention:

1. In a variable resistance device, a vessel, a liquid having a high resistance disposed therein and means for continuously varying the effective resistance of said liquid, said means comprising a pair of rotatably mounted conductors having portions contained in said liquid, said conductors being so arranged that the spacing thereof with respect to said liquid is continuously varied for a movement of said conductors.

2. A variable-resistance device comprising a container, a body of liquid having a high resistance contained therein, a pair of curved conductors carried by said container and having corresponding portions positioned in said liquid in spaced relation, said conductors bein so curved that their relative spacing W1th respect to said liquid varies with the rotation of said container.

3. A variable-resistance device comprising a container, at body of liquid containing alcohol and xylol disposed therein, and a pair of curved conductors carried by said container, and having corresponding portions positioned in said liquid in spaced relation, said conductorsbeing so curved that their relative spacing with respect to said liquid varies with the rotation of said container.

4. A variable-grid-leak device comprising a container of insulating material containing alcohol and xylol disposed therein, and a pair of curved conductors carried by said container and having corresponding portions positioned in said liquid in spaced relation, said conductors being so curved that their relative spacing with respect to said liquid varies with the rotation of said container.

5. A variable-resistance device comprising a container, a conducting liquid therein, a solid conductor having a helically shaped contact surface partially immersed in said liquid, the axis of said helically shaped surface being horizontal, and means for rotating said solid conductor about its axis.

6. A variable-resistance device comprising a horizontal tubular container, a small quantity of a conducting liquid therein, a solid conductor having a helically shaped contact surface mounted in said tubular container, and means for rotating said tubular container about its axis.

7. A variable-resistance device comprising a container, conducting liquid therein, a pair of electrodes carried by said container and means for rotating said container about an axis inclined to the vertical, the relative proportions and arrangements of the parts being such that the points of contact of the liquid and the electrodes are varied in accordance with the rotative movement of said container.

In testimony whereof, I have hereunto subscribed my name this 21st day of September, 1922.

LEE SUTHERLIN. 

